1. Field of the Invention
The present invention relates to a vehicle projection lamp having a convex lens and an ellipsoidal reflector enclosing a light source.
2. Discussion of the Related Art
FIG. 9 shows a conventional vehicle head lamp. The vehicle head lamp includes a substantially ellipsoidal reflector 3 with a light source 4 positioned substantially at a first focal point, and a convex lens 6 (a projection convex lens) attached to a cylindrical lens holder 5 and having a focal point such that light reflected by the reflector 3 is focused. A lamp chamber is enclosed by a lamp body 1 and a front cover 2.
The convex lens 6 is secured by a front end side opening portion of the lens holder 5 with a ring-like fastening band 7. The lens holder 5 is secured to the reflector 3 with bolts and nuts (not shown). A shade 5a forms a clear cut line in passing beams of light.
The conventional projection head lamp can be small and can supply a large amount of light because the reflector 3 can be small compared to a reflection head lamp with a parabolic reflector. The conventional projection head lamp described above has been used in recent years in automotive applications.
However, because the conventional projection head lamp uses the fastening band 7 to secure the convex lens 6 to the lens holder 5, the number of parts of the projection head lamp is large, and assembling the convex lens 6 into the lens holder 5 is inconvenient.
Further, if the projection head lamp is used as a vehicle head lamp, light distribution may fluctuate because vibration acts on the vehicle head lamp, and the fastening band 7 may loosen after passage of time.